This invention relates to modulation devices for light beams. More particularly, this invention relates to the use of partially transparent reflector stacks which are physically displaced relative to each other to accomplish the modulation of a beam which is either transmitted through or reflected from the ensemble of partially transparent reflector stacks depending on the modulation state.
This modulator is designed to operate upon a collimated or nearly collimated beam of light to achieve modulation by means of either electrical, mechanical or acoustical input signals to the device. This is a accomplished by varying the spacing between two partially transparent reflector stacks by means of piezo-electric, electrostatic, magnetic or magneto strictive manipulation or direct mechanical or acoustical manipulation of the spacing between the partially transparent reflector stacks.
The partially transparent reflector stacks are made up by a carefully controlled sequence of deposition of alternating layers of high and low index of refraction materials, each of which is a precisely controlled fraction in optical thickness reference to the wavelength of the light beam.
Present means of achieving optical modulation of light require the light to be transmitted a macroscopic distance through a non-linear optical material subject to optical damage and degradation by exposure to ionizing radiation. For example, Kerr and Pockels cells and other similar devices have been utilized to Q-switch light beams. However, these devices are rather cumbersome and require relatively high voltages to operate. Some of these devices also require associated polarizing components for their operation. The present device in contrast can be made to have an optical length of less than a millimeter. It is a stand alone device which does not require separate polarizing components and can be designed for inherent stability at a given wavelength and in an environment which contains high levels of ionizing radiation.